drm/i915: Be more careful when picking the initial power sequencer pipe

Try to make sure we find the power sequencer that the BIOS used
by first looking for one which has the panel power enabled, then
fall back to one with VDD force bit enabled, and finally look at
just the port select bits. This should make us pick the correct
power sequencer when the BIOS has already enabled the panel.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
[danvet: Shorten the vlv_intial_pps_pipe to make lines fit into 80
chars.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_dp.c

@@ -375,9 +375,31 @@ vlv_power_sequencer_pipe(struct intel_dp *intel_dp)
 	return intel_dp->pps_pipe;
 }
 
+typedef bool (*vlv_pipe_check)(struct drm_i915_private *dev_priv,
+			       enum pipe pipe);
+
+static bool vlv_pipe_has_pp_on(struct drm_i915_private *dev_priv,
+			       enum pipe pipe)
+{
+	return I915_READ(VLV_PIPE_PP_STATUS(pipe)) & PP_ON;
+}
+
+static bool vlv_pipe_has_vdd_on(struct drm_i915_private *dev_priv,
+				enum pipe pipe)
+{
+	return I915_READ(VLV_PIPE_PP_CONTROL(pipe)) & EDP_FORCE_VDD;
+}
+
+static bool vlv_pipe_any(struct drm_i915_private *dev_priv,
+			 enum pipe pipe)
+{
+	return true;
+}
+
 static enum pipe
-vlv_initial_power_sequencer_pipe(struct drm_i915_private *dev_priv,
-				 enum port port)
+vlv_initial_pps_pipe(struct drm_i915_private *dev_priv,
+		     enum port port,
+		     vlv_pipe_check pipe_check)
 {
 	enum pipe pipe;
 
@@ -388,6 +410,9 @@ vlv_initial_power_sequencer_pipe(struct drm_i915_private *dev_priv,
 		if (port_sel != PANEL_PORT_SELECT_VLV(port))
 			continue;
 
+		if (!pipe_check(dev_priv, pipe))
+			continue;
+
 		return pipe;
 	}
 
@@ -406,7 +431,17 @@ vlv_initial_power_sequencer_setup(struct intel_dp *intel_dp)
 	lockdep_assert_held(&dev_priv->pps_mutex);
 
 	/* try to find a pipe with this port selected */
-	intel_dp->pps_pipe = vlv_initial_power_sequencer_pipe(dev_priv, port);
+	/* first pick one where the panel is on */
+	intel_dp->pps_pipe = vlv_initial_pps_pipe(dev_priv, port,
+						  vlv_pipe_has_pp_on);
+	/* didn't find one? pick one where vdd is on */
+	if (intel_dp->pps_pipe == INVALID_PIPE)
+		intel_dp->pps_pipe = vlv_initial_pps_pipe(dev_priv, port,
+							  vlv_pipe_has_vdd_on);
+	/* didn't find one? pick one with just the correct port */
+	if (intel_dp->pps_pipe == INVALID_PIPE)
+		intel_dp->pps_pipe = vlv_initial_pps_pipe(dev_priv, port,
+							  vlv_pipe_any);
 
 	/* didn't find one? just let vlv_power_sequencer_pipe() pick one when needed */
 	if (intel_dp->pps_pipe == INVALID_PIPE) {